For purposes of effecting economy in the lumber industry and also to maximize the production of useable lumber pieces from logs, both large and small, numerous attempts have been made in the development of machinery to saw and otherwise convert round logs into such useful articles of lumber. Typical of some of these prior references are the following U.S. Pat. Nos.:
555,037, Dees, Feb. 18, 1896 PA0 3,259,157, Runnion, July 5, 1966 PA0 3,304,971, Pease, Feb. 21, 1967 PA0 3,313,329, Mitten, April 11, 1967 PA0 3,552,457, Bos, Jan. 5, 1971
The Dees patent shows several systems for sawing logs into boards in order to maximize the number and shapes of boards produced by a single log. Runnion is concerned primarily with producing dimensional or useful lumber from small-diameter logs and incident to doing so, ribs are formed with parallel sides on the bottoms of the logs and these are used to guide the logs through the mill apparatus. Pease also forms useful lumber pieces from small-diameter logs and employs both chipping and sawing to accomplish the same. The Mitten patent is a more recent development than the prior patents referred to above and pertains to a machine for cutting by chipping two diametrically opposite flat surfaces respectively from the top and bottom of logs and also forms a segment and two notches, said flat surfaces and inner walls of the notches being employed as bearing surfaces to guide the log during the following stages of treatment.
The Bos patent pertains to forming a square cant as well as chipping outer portions of a log to form the outer surfaces of boards respectively sawed from the ultimate faces of the square cant. During the processing of the log, a central chipper head forms a V-shaped notch in the top of the log, followed by additional chipper heads respectively chipping flat surfaces at a right angle to each other respectively at opposite sides of said central chipper head while the original curved surface on the bottom of the log is supported by appropriate rollers. After shaping the log to form two boards on the opposite sides of the central upper V-shaped notch and sawing the boards therefrom, it is necessary to rotate the log 180.degree. in order to similarly process the initial lower half of the log into two additional boards and also form the remaining two surfaces of the square cant. Sawing of the boards from the cant is accomplished by band saws spaced longitudinally along the path of travel of the log and then after the log is turned following the completion of the formation of the two upper surfaces of the cant and removal of the two top boards, another pass, separate from the first pass, must be made in order to process the bottom half of the log to equal the product produced by the first pass through the machine, such additional passage through the machine being time-consuming, as well as requiring means to rotate the log 180.degree. between passes.